adsorption of malachite green using activated carbon from … · 2018-09-01 · adsorption of...

IOSR Journal of Applied Chemistry (IOSR-JAC)

e-ISSN: 2278-5736.Volume 11, Issue 8 Ver. I (August. 2018), PP 33-45

www.iosrjournals.org

DOI: 10.9790/5736-1108013345 www.iosrjournals.org 33 |Page

Adsorption of Malachite Green Using Activated Carbon From

Copper Pod

Saravanan N1, Rathika G

2

1 Department of Chemistry, Nandha Engineering College, Erode-638052, Tamil nadu, India.

2 Department of Chemistry, PSG College of Arts and Science, Coimbatore-641014, Tamil nadu, India.

Corresponding Author: Saravanan N

Abstract: In the present study, the adsorption capacity of waste materials of copper pod fruit was determined

for the removal of malachite green dye from aqueous solutions. This batch adsorption experiment was carried

out to study for the various parameters such as adsorbent dosage, contact time, initial metal ion concentration,

pH value and temperature. The morphology was investigated by scanning electron microscope and X-Ray

diffraction data. The equilibrium data in aqueous solution were analysed using Freundlich, Langmuir isotherm

model, Tempkin and Dubinin - Radushkevich isotherm. Adsorption isotherm of malachite green dye obeyed

Langmuir isotherm model, Tempkin and Dubinin - Radushkevich isotherm. The kinetic data in aqueous solution

were studied using Pseudo-first and Pseudo-second order kinetic models, Intraparticle diffusion and Elovich

model. It was found that the adsorption of malachite green onto copper pod fruit activated carbon (CPFAC)

followed pseudo second order kinetic model and Elovich model. The high values of correlation coefficient (R2)

of intraparticle diffusion model indicated that the pore diffusion plays a significant role for the adsorption.The

results indicate that the activated carbon prepared from copper pod fruit could be employed as a low-cost

alternative to commercial activated carbon for the elimination of malachite green from waste water and

aqueous solutions.

Keywords : Adsorption, Copper pod fruit, Isotherm, Kinetic and Malachite green.

----------------------------------------------------------------------------------------------------------------------------- ----------

Date of Submission: 20-08-2018 Date of acceptance: 03-09-2018

----------------------------------------------------------------------------------------------------------------------------- ----------

I. Introduction In textile industry dyes are used to colour their products. Decolourisation of wastewater has become

one of the major issues in wastewater pollution [1]. Wastewater from the textile industry is directly released into

the nearby water bodies or on land [2]. These wastewaters have polluted nearby water bodies and have been

reported to be slightly toxic even at low concentration. The disposal of such wastewater containing dyes can

affect the quality of the receiving water bodies and aquatic ecosystem due to its toxicity, high BOD and COD

value [3]. Pollution degrades the environment, which in turn leads to the depletion of the earth’s ozone layer and

makes a hole in the ozone cover [4]. There are different views regarding the origin of pollution crisis on the

planet earth. These environments affected by developed countries and yet population, municipal wastes,

industrial wastes, automobile gases, agricultural wastes, solid wastes and disposable wastes [5]. These above

factors are produced different type of pollutions like global warming, greenhouse effect, acid precipitations, air

pollution, water pollution, noise pollution, soil pollution. These pollutions are affecting the quality of life of the

living – non living organisms –present and future. Therefore treatment of these pollutions is very important.

Several physical, chemical and biological methods have been used for eliminating dyes from textile waste water

[7]. Some conventional methods such as membrane process, electrochemical techniques, reverse osmosis,

coagulation, flocculation, ultra-filtration, biological process, chemical reaction, photo oxidation, precipitation

have been used for eliminating dyes from textile waste water [8]. Most of these methods are expensive due to

their high capital and operational costs. Among these methods, activated carbon is a widely used method for

removal of colour from wastewater because of its well developed porous structure and tremendous surface area

[9]. In the present study, copper pod fruit activated carbon (CPFAC) has been used as a new low - cost

adsorbent for removal of dye from textile waste water. The effect of various operating parameters such as

adsorbent dosage, contact time, initial metal ion concentration, pH and temperature were studied.

II. Materials And Methods 2.1. Adsorbent preparation

The present studies Copper Pod were used as adsorbent for the removal dye from aqueous solution.

They were collected from in around PSG College of Arts and Science, Coimbatore District, Tamilnadu, India

which were available in abundant.

Adsorption of Malachite Green Using Activated Carbon From Copper Pod


The copper pod fruit was first peeled off to obtain the outer skin of the fruit and then removal of

the inner fleshy layer. The peel was washed with ordinary tap water to remove any dirt and sands. The washed

materials were dried in sun light to evaporate the moisture present in it. The dried materials were carbonized

with 1:1 Sulphuric acid. The charred material was filtered and washed with excess of water to remove residual

acid from pores of the carbon particles. The filtered material was kept in muffle furnace at 600 ºC for 30

minutes. The carbonized material was ground to fine powder and then sieved with a particle size of 53 𝜇𝑚. The

sieved adsorbent was kept in an airtight container for further adsorption studies.

2.2. Preparation of Adsorbate

A stock solution of malachite green was prepared by dissolving 1 gm of the malachite green dye in a

1litre of distilled water to give concentration of 1000mg/L. The working solutions were prepared by diluting the

stock solution with distilled water to get the appropriate concentration of the working solutions. The dye

concentration was determined using uv/visible spectrometer at a max value of 617nm.

2.3. Effect of adsorbent dosage

The effect adsorbent dosage was studied by preparing different dye concentration (10, 20, 30, 40 & 50

mgs/lit) and different adsorbent dosage (0.1 – 1g). 50ml of dye solution was added to different 250ml conical

flask containing different dosage of the adsorbents (0.1 – 1g).The conical flasks were well corked and agitated

in a shaker. After agitation, the solution was filtered and analysed using digital spectrophotometer.

2.4. Effect of contact time

The effect of contact time on the amount of dye removal was studied for a period of 100min. 50ml of the dye

solution (10, 20, 30, 40 &50ppm) was added to different 250ml conical flask containing 0.1g of the adsorbents.

The conical flask was well corked and agitated in a shaker. The solution was filtered and analysed after each

agitated time.

2.5. Effect of pH

The effect of pH on amount adsorbed was studied by various pH of the solution from 2 to 12. 50ml of

(10, 20, 30, 40 & 50ppm) dye solution of known initial pH was added to different conical flask containing 1gm

of the adsorbent. The pH was controlled using 0.1M HCl or 0.1M NaOH and was measured using pH meter.

The mixture of the conical flask solution was well corked and agitated in a shaker. The mixture of the conical

flask solution was filtered after the agitated time. The concentration of the dye in the filtrate was analysed using

digital spectrophotometer.

2.6. Effect of Temperature

The effect of temperature on the amount of dye removal was studied for different temperatures. 50ml

of (10, 20, 30, 40 &50ppm) dye solution was agitated with 0.1gm of the adsorbent for different temperatures

using shaker.

III. Results And Discussion 3.1. Effect of contact time and initial dye concentration

The effect of contact time on percentage of dye removal using copper pod at different initial concentration is

shown in figure.1.

Fig.1: Effect of initial concentrations on the adsorption of Malachite green onto CPFAC.

0.00

20.00

40.00

60.00

80.00

100.00

120.00

0 10 20 30 40 50 60 70 80 90 100

% R

emo

va

l

Time (min)

10 ppm

20 ppm

30 ppm

40 ppm

50 ppm



The result (figure.1.) indicates that the percentage of dye removal increases in contact time and became constant

when equilibrium was reached. The percentage of dye removal decreased with increase in initial dye

concentration. It was seen that the adsorption of dye depends on its concentration [10]. The amount of dye

adsorbed increases due to the increased number of active adsorption or bonding sites [11]. After attained

equilibrium, there is no significant change in adsorption.

3.2. Effect adsorbent dosage

The effect of adsorbent dosage on the percentage removal of dye is shown in figure.2. Shows that increased

adsorbent dosage increase the percentage of dye removal. Higher dosage of adsorbent increased the percentage

of dye removal due to more surface area and functional groups or more binding sites are available on the carbon

[12]. Further increase in adsorbent dose, there is no significant increase in adsorption [13].

Fig.2: Effect of adsorbent dosages on the adsorption of Malachite green onto CPFAC.

3.3. Effect of pH

The pH of the adsorption has important parameters for controlling the percentage of dye removal.

Figure.3. indicates that the effect of pH on the percentage removal of dye in the presence of activated carbon.

The percentage of dye removal was increased with increase in initial pH of the dye solution from 2 to 7 and

decreased with increase of pH of the dye solution from 8 – 12. This is due to the nature of the adsorbent [14].

Fig.3: Effect of pH on the adsorption of Malachite green onto CPFAC.

0.00

20.00

40.00

60.00

80.00

100.00

120.00

0 100 200 300 400 500 600 700 800 900 1000

% R

emo

va

l

Adsorbent Dosages (mg)

10 ppm

20 ppm

30 ppm

40 ppm

50 ppm

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

0 2 4 6 8 10 12 14

% R

emo

va

l

pH

10ppm

20ppm

30ppm

40ppm

50ppm



3.4. Effect of Temperature

The effect of temperature on the removal of dye solution is shown in figure.4. It is clear that the

percentage of dye removal decrease with increase in temperature for 40mgs/lit. It can be seen that the adsorption

is exothermic in nature, and then high temperatures would inhibit or slow down the adsorption process [15].

Fig.4: Effect of temperature on the adsorption of Malachite green onto CPFAC.

3.5. Scanning Electron Microscope analysis

The SEM photograph of the adsorbent is shown in figure.5. SEM characterization of adsorbent showed

different structural features with non-uniform sizes and complete change in surface texture [16]. From the

figure, it was also observed that wide varieties of pores and rough surface are present in the adsorbents. Pores

development in an adsorbent is important since pores act as active sites or bonding sites which played the main

role in adsorption [17]. The cavities and granular pores will increase the surface area of the adsorbent. The

surface area of the adsorbents will be enhanced by the presence of more porosity, which can hold more solute

from solution during adsorption [18]. These changes in the SEM morphologies are very good agreement with

the literature for various materials [19, 20, 21].

Fig.5: SEM image of activated carbon treated with Sulphuric acid

3.6. Powder X-ray diffraction study

The powder X-ray diffraction analysis of sample AC-H2SO4 investigated and displayed in Figure.6. In

activated carbons, a broad peak due to reflections from the planes can be clearly seen. The broadness of the peak

indicates the amorphous nature of the carbon sample [22, 23].

0.00

20.00

40.00

60.00

80.00

100.00

0 20 40 60 80 100 120

% R

emo

va

l

Time (min)

30°C

40°C

45°C

50°C

55°C

60°C



Fig.6: XRD pattern for prepared activated carbon

Figure shows XRD spectrum of the adsorbent. This spectrum clearly shows that the particle size is

responsible for the broadening peaks in the XRD pattern [24, 25]. This spectrum also indicates that the presence

of amorphous form of carbon which is disorderly stacked up by carbon rings.

3.7. Analysis of adsorption Kinetics

Kinetic models are used to study the rate of the adsorption process and factors affecting adsorption rate [26].

The following three kinetic models were used to explain the experimental data.1.Pseudo first order equation 2.

Pseudo second order equation 3. Intra particular diffusion equation.

3.7.1. Pseudo-first order equation

The pseudo- first order equation of lagergen is expressed as follows.

log 𝑞𝑒 − 𝑞𝑡 = log 𝑞𝑒 −𝑘1𝑡

2.303 (1)

Where, 𝑞𝑒 is the amount of dye removed at equilibrium (mg/g)

𝑞𝑡 is the amount of dye removed at time t (mg/g)

𝑘1 is the pseudo- first order rate constant (min-1

)

A plot of log 𝑞𝑒 − 𝑞𝑡 versus time (t) gives a straight line and is shown in figure.7. The values of 𝑘1 and 𝑞𝑒

can be calculated from the slope and intercept of the linear plot. The pseudo first order rate constant (𝑘1),

correlation coefficients (R2), experimental 𝑞𝑒 values and calculated 𝑞𝑒 values are illustrated in table.1. There is

no close difference between the experimental 𝑞𝑒 values and calculated 𝑞𝑒 values [27, 28]. It can be concluded

that the adsorption of malachite green dye on CPFAC did not follow the pseudo first order reaction.

Fig.7: Pseudo-first order kinetics for adsorption of Malachite green onto prepared activated carbon at 30°C

y = -0.007x + 0.161

R² = 0.447

y = -0.008x + 0.433

R² = 0.633

y = -0.009x + 0.575

R² = 0.738

y = -0.012x + 0.905

R² = 0.829

y = -0.012x + 1.005

R² = 0.855

-1.000

-0.800

-0.600

-0.400

-0.200

0.000

0.200

0.400

0.600

0.800

1.000

0 20 40 60 80 100 120log

(qe-q

t)

Time (min)

10 ppm

20 ppm

30 ppm

40 ppm

50 ppm



3.7.2. Pseudo-second order equation

The pseudo second order equation is expressed as follows. 𝑡

𝑞𝑡=

1

𝑘2𝑞𝑒2 +

𝑡

𝑞𝑒 (2)

Where, 𝑞𝑒 is the amount of dye removed at equilibrium (mg/g)

𝑞𝑡 is the amount of dye removed at time t (mg/g)

𝑘2 is the pseudo- second order rate constant (min-1

)

If the pseudo second order kinetic model is follow, the plot of 𝑡

𝑞𝑡versus t should give a linear

relationship. 𝑘2 and 𝑞𝑒 values can be determined from the slope and intercept of the plot are presented in

table.1.The figure.8 shows various initial dye concentration and temperature of pseudo second order. The

experimental data (𝑞𝑒), rate constants(𝑘2) and correlation coefficients (R2) are shown in table.1. It can be

concluded that R2 values for the pseudo second order kinetic model is higher than that of R

2 values for the

pseudo first order kinetic model for all initial malachite green concentrations [29, 30]. There is close difference

between the experimental 𝑞𝑒 values and calculated 𝑞𝑒 values [28, 29]. It can be said that the adsorption of

malachite green on CPFAC is well suitable for the pseudo second order kinetics model compared to the pseudo

first order model.

Fig.8: Pseudo- second order Kinetics for the adsorption of Malachite green onto prepared activated carbon at

30°C

Table 1: Pseudo first and pseudo second order kinetic parameters for different initial dye concentration Intial Conc.(ppm) Pseudo-first order kinetic model Pseudo-second order kinetic model

qeexp (ppm) qecal (ppm)

k1

(ppm) R2 qeexp

(ppm) qecal (ppm) k2

(ppm) R2

10 9.87 1.448 0.0161 0.447 9.87 9.43 0.0891 0.985

20 19.44 2.710 0.0184 0.633 19.44 18.86 0.0334 0.986

30 28.26 3.758 0.0207 0.738 28.26 27.02 0.0204 0.987

40 36.34 8.035 0.0276 0.829 36.34 35.71 0.0290 0.984

50 43.21 10.115 0.0276 0.855 43.21 41.66 0.0320 0.984

3.7.3. Intra particle diffusion studies

Intra particle diffusion model is used for identifying the mechanism involved in the adsorption process [30].

Intraparticle diffusion (kd) is given by weber morris and is expressed as follows

𝑞𝑡= 𝑘𝑑𝑡1/2 (3)

Where, 𝑞𝑡 is the amount adsorbed (mgg-1

) at time t(min).

𝑘𝑑 is the rate constant of intraparticle diffusion(mgg-1

min1/2

).

If the mechanism of adsorption process obey the intraparticle diffusion, the plot of amount adsorbed

(qt) versus time would be a linear relationship and is shown in figure.9.The rate constant of intraparticle

y = 0.106x - 0.126

R² = 0.985

y = 0.053x - 0.084

R² = 0.986

y = 0.037x - 0.067

R² = 0.987

y = 0.028x - 0.027

R² = 0.984

y = 0.024x - 0.018

R² = 0.984

0.000

2.000

4.000

6.000

8.000

10.000

12.000

0 10 20 30 40 50 60 70 80 90 100

t/q

t

Time (min)

10 ppm

20 ppm

30 ppm

40 ppm

50 ppm



diffusion (𝑘𝑑 ) can be calculated from slope of the plot and the values are illustrated in table.2. The initial portion

of the intraparticle diffusion plot indicates that a boundary layer effect while the second portion of the linear

curve is due to intraparticle diffusion [29]. The linear portion of the plot did not pass through the origin indicates

that intraparticle diffusion is not the only rate controlling step, and also other mechanism may control the

adsorption rate [31]. The high values of correlation coefficient (R2) indicated that the pore diffusion plays a

significant role for the adsorption of Malachite green dye onto the activated carbon prepared from copper pod

fruit. This result also revealed that the intra particle diffusion process is supposed to be rate-limiting step.

Fig.9: Intra particle diffusion for the adsorption of Malachite green onto prepared activated carbon at 30°C

Table 2: Intra Particle Diffusion model Initial Concentration (ppm) Intra Particle Diffusion model

C Kd (mg/g.min) R2

10 8.42 0.014 0.974

20 17.08 0.024 0.988

30 25.12 0.033 0.973

40 30.75 0.060 0.974

50 36.54 0.071 0.987

3.7.4. Elovich Model

Elovich model can be expressed as follows

tqt e

dt

dq (4)

Where, α is the initial adsorption rate constant (mg/g min) and β is related to the extent of surface coverage and

activation energy for chemisorption (g/mg).

Integrating this equation for the boundary conditions, expressed as follows

𝑞𝑡 = 1/ 𝛽[ 𝑙𝑛(𝛼𝛽)] + 1/ 𝛽 𝑙𝑛 𝑡 (5) α and β values can be determined from the slope and intercept of plot qt Vs lnt. Figure 10 illustrates the

Elovich isotherm model for the dye adsorption onto the adsorbents from which the relevant isotherm parameters

are listed in table.3. It has been suggested that decrease in β value would increase the rate of the adsorption

process [32]. There is linear plot with good correlation coefficient (R2) values ranges from 0.973 to 0.988, which

gave a close fit to the malachite green adsorption on CPFAC.

y = 0.014x + 8.426

R² = 0.974

y = 0.024x + 17.08

R² = 0.988

y = 0.033x + 25.12

R² = 0.973y = 0.060x + 30.75

R² = 0.974

y = 0.071x + 36.54

R² = 0.987

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

0 10 20 30 40 50 60 70 80 90 100

qt(

mg

/g)

t 1/2

10

ppm

20

ppm

30

ppm

40

ppm



Fig.10: Elovich model for the adsorption of Malachite green onto prepared activated carbon at 30°C.

Table 3: Elovich model Initial Concentration (ppm) Elovich model

β R2

10 6.802 0.974

20 4.065 0.988

30 3.012 0.973

40 1.658 0.974

50 1.404 0.987

3.8. Adsorption isotherm

The adsorption isotherm describes the mechanism of the adsorption process between the adsorbate and the

adsorbent [18, 20]. The Langmuir and Freundlich isotherm were analysed to study the adsorption isotherm.

3.8.1. Langmuir isotherm

The linear form of langmuir isotherm equation is expressed as follows.

𝐶𝑒

𝑞𝑒=

1

𝑄0𝑏+

𝐶𝑒

𝑄0 (6)

Where, 𝑞𝑒 is the amount of dye adsorbed at equilibrium (mgg-1

)

𝐶𝑒 is the concentration of dye solution at equilibrium (mgL-1

)

𝑄0 is Langmuir constant related to adsorption capacity (mgg-1)

b is Langmuir constant related to rate of adsorption(Lmg-1)

A plot of 𝐶𝑒

𝑞𝑒 versus 𝐶𝑒 gives a straight line with slope of

1

𝑄0 and intercept of

1

𝑄0 b and is shown in figure.11.

Fig.11: Langmuir isotherm for the adsorption of Malachite green onto prepared activated carbon.

y = 0.147x + 8.426

R² = 0.974

y = 0.246x + 17.08

R² = 0.988

y = 0.332x + 25.12

R² = 0.973

y = 0.603x + 30.75

R² = 0.974

y = 0.712x + 36.54

R² = 0.9870.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

0 2 4 6 8 10 12

qt(

mg

/g)

lnt

10ppm

20 ppm

30 ppm

40 ppm

50 ppm

y = 0.013x + 0.041

R² = 0.997y = 0.012x + 0.058

R² = 0.993

y = 0.011x + 0.089

R² = 0.967y = 0.011x + 0.105

R² = 0.963

y = 0.013x + 0.132

R² = 0.981y = 0.014x + 0.143

R² = 0.9850.00

0.10

0.20

0.30

0.40

0.50

0.60

0.00 5.00 10.00 15.00 20.00 25.00 30.00

Ce/

qe

Ce

30°C

40°C

45°C

50°C

55°C

60°C



Table 4: Langmuir isotherm parameters Temp.(Dc) Langmuir Constants

R2 Q0(mg/g) b. (L/mg)

30 0.997 76.92 0.3170

40 0.993 83.33 0.2068

45 0.967 90.90 0.1235

50 0.963 90.90 0.1047

55 0.981 76.92 0.0984

60 0.985 71.42 0.0979

𝑄0 and b values are decreases with increase in temperature. The experimental data indicates that the

amount of malachite green dye adsorbed on adsorbents decreased with increasing temperature from 30oC to

60oC.The linearity of the plots and high correlation co-efficient (R

2) values indicated that the adsorption process

obeys the Langmuir isotherm model with monolayer adsorption[33, 34]. This result clearly indicates that the

adsorption of malachite green dye on activated carbon prepared from copper pod fruit takes place as monolayer

adsorption on the surface of the adsorbent, homogenous in adsorption affinity and with constant adsorption

energy.

The constant (Q0) is a measure of maximum adsorption capacity of the adsorbent under the

experimental conditions. The constant (b) decreased from 0.3170 to 0.0979 with the increased temperature of

30oC to 60

oC. The result indicates that the maximum adsorption occurs at temperature 30

oC.

The essential characteristics of Langmuir isotherm equation can be expressed in terms of dimensionless

separation factor, RL, which is defined by the following equation.

𝑅𝐿 = 1

1+𝑏𝑐0 (7)

Where C0 is the initial concentration of dye solution (mgL-1

) and b is the Langmuir constant. The value

of RL indicates that the shape of the adsorption isotherm to be either linear (RL =1), favourable (0<RL<1),

unfavourable (RL>1), or irreversible (RL=0) [26, 28]. The values of RL are shown in table .5. A low value of RL

favours adsorption [23]. The RL values for the present experiment data fall between 0 and 1, which is an

indication of the favourable adsorption process.

Table 5: RL values at various initial dye concentration Initial Dye RL Value

Concentration

(ppm)

300C 400C 450C 500C 550C 600C

10 0.2397 0.3258 0.4472 0.4883 0.5038 0.5053

20 0.1362 0.1946 0.2880 0.3230 0.3367 0.3380

30 0.0951 0.1387 0.2124 0.2413 0.2528 0.2539

40 0.0730 0.1078 0.1682 0.1926 0.2024 0.2034

50 0.0593 0.0881 0.1392 0.1603 0.1687 0.1696

3.8.2. Freundlich Isotherm

The Freundlich isotherm equation is expressed as follows

𝑙𝑜𝑔 𝑞𝑒 = 𝑙𝑜𝑔𝑘𝑓 + 1

𝑛 log𝐶𝑒 (8)

Where, 𝑞𝑒 is the amount of dye adsorbed (mg g-1

)

𝐶𝑒 is the concentration of dye solution at equilibrium (mgL-1

)

𝑘𝑓 is Freundlich constant related to the adsorption capacity of adsorbent

n is Freundlich constant related to the adsorption intensity

𝑘𝑓 and n values can be calculated from the slope of the straight line and is shown in figure.12.



Fig.12: Freundlich isotherm for the adsorption of Malachite green onto prepared activated carbon.

Table 6: Freundlich isotherm parameters Temp.(0 0C) Statistical Parameters / Constants

R2 n Kf (mg/L)

300C 0.924 2.2123 19.998

400C 0.948 1.9920 16.481

450C 0.915 1.6920 11.994

500C 0.915 1.6611 10.665

550C 0.950 1.6863 9.099

600C 0.958 1.7605 8.729

The value of R2 is used to measure goodness of fit of experimental results on the adsorption isotherm

models [35, 30]. According to the adsorption isotherm results, the Langmuir isotherm (R2= 0.963 to 0.997) is

more favourable than Freundlich isotherm (R2= 0.924 to 0.958). The adsorption process is said to be favourable

[33, 21] when the value of n satisfies the condition n<1, otherwise it is unfavourable. While the n values in

Table.6 for adsorption of malachite green dye on CPFAC are situated outside the range of 0 to 1 indicating

unfavourable adsorption process.

3.8.3 Tempkin isotherm

The linear form of Tempkin isotherm equation is given as follows

𝑞𝑒 = 𝐵 (𝑙𝑛𝐴 + 𝑙𝑛𝐶𝑒) (8) Where, B is the Tempkin constant related to heat of adsorption

A is the equilibrium binding constant (mg/l)

The values of the Tempkin constants A and B can be determined from the intercept and slope of the linear plot

of lnCe versus qe and is shown in Figure.13. The correlation coefficients (R2) values are listed in Table.7.The

result shows that the values of R2

are located in the range of 0.976 to 0.985, which indicate a better fits to the

malachite green adsorption onto CPFAC.

y = 0.452x + 1.301

R² = 0.924

y = 0.502x + 1.217

R² = 0.948

y = 0.591x + 1.079

R² = 0.915

y = 0.602x + 1.028

R² = 0.915

y = 0.593x + 0.959

R² = 0.950

y = 0.568x + 0.941

R² = 0.9580.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60

log

qe

log Ce

30°C

40°C

45°C

50°C



Fig.13: Tempkin isotherm for the adsorption of Malachite green onto prepared activated carbon.

Table 7: Tempkin isotherm parameters Temp.(0 0C) Statistical Parameters / Constants

R2 B A

300C 0.976 16.84 2.5069

400C 0.978 18.09 4.4694

450C 0.980 18.29 0.0577

500C 0.982 19.87 0.0417

550C 0.985 17.96 0.0011

600C 0.983 16.34 0.0011

3.8.4. Dubinin – Radushkevich isotherm

The linear form of the Dubinin-Radushkevich isotherm equation can be expressed as follows

ln qe = ln Xm - β E2

(9) Where,

Xm is the theoretical saturation capacity (mg/g), β is a constant related to mean free energy of adsorption per

mole of the adsorbate (mol2/J

2) and E

2 is the Polanyi potential. The values of E, Xm and β can be calculated

from the slope and intercept of the plot of E2

versus ln qe gives a straight line and is shown in figure.14.The

correlation coefficients (R2), E, Xm and β values are listed in Table.8.

The mean free energy of adsorption E is determined from β using the following equation

E = 1/ (2β)1/2

(10) The

activation energy of adsorption decreases with increase of temperature from 30 to 60 0C. The values correlation

coefficients (R2) are in the range of 0.911 to 0.969, revealing that the experimental data fitted well with the

Dubinin-Radushkevich isotherm model. Based on this energy of activation one can predict whether an

adsorption is physisorption or chemisorptions [36]. If the energy of activation is, <8 kJ mol−1

, the adsorption is

physisorption. If the energy of activation is >8 kJ mol−1

, the adsorption is chemisorptions [37, 38]. From table.8,

it can be observed that the obtained the obtained values of mean free energy, E, are limited within the range of

34.921 to 48.795 kJ mol-1

. Based on these data, it can be concluded that the effect of chemical adsorption will

play a dominating role in the adsorption process of malachite green dye onto the adsorbents.

y = 16.84x + 18.32

R² = 0.976

y = 18.09x + 12.08

R² = 0.978

y = 20.29x + 2.411

R² = 0.980

y = 19.87x - 0.253

R² = 0.982

y = 17.96x - 2.646

R² = 0.985y = 16.34x - 2.383

R² = 0.983

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50

qe(

mg

/g)

ln ce

30°

C

40°

C



Fig.14: Dubinin -Radushkevich isotherm model for the adsorption of Malachite green onto prepared activated

carbon.

Table 8: Dubinin -Radushkevich isotherm parameters Temp.(0 0C) Statistical Parameters / Constants

R2 Xm (mg/g) E (KJ/mol)

300C 0.925 56.163 34.921

400C 0.891 53.746 28.629

450C 0.969 55.494 67.419

500C 0.969 53.425 48.795

550C 0.929 46.866 48.795

600C 0.918 43.567 48.795

IV. Conclusion The adsorption data for the uptake of malachite green dye increased with increase in initial

concentration, contact time and adsorbent dosages. The adsorption process is an exothermic. The optimum

temperature was found to be 300C. The effect of pH on the dye solution is most important parameter in

adsorption process. The maximum dye adsorption occurred at a pH 7.0. The adsorption isotherm data was well

described with Langmuir isotherm model, Tempkin and Dubinin - Radushkevich isotherm better than

Freundlich isotherm model. RL values indicate favorable adsorption process. The adsorption processes for

malachite green dyes were found to follow the pseudo-second order kinetic model, intraparticle diffusion model

and Elovich model. The SEM study observed that difference in surface morphology of adsorbent. Finally, the

results clearly indicated that copper pod fruit activated carbon(CPFAC) could be used as an alternative to highly

efficient low cost and abundant materials for removal of malachite green dye from contaminated aqueous

solutions.

Acknowledgment Authors are thankful to the Principal and the Head, Department of Chemistry, PSG College of Arts and Science,

Coimbatore, Tamil Nadu, India for providing laboratory facilities for the work. I also thank all the faculty

members for their help during the project.

References [1]. N. Emad, J. Stephen, and M. Gavin, Adsorption of methylene blue onto activated carbon produced from steam activated bituminous

coal: a study of equilibrium adsorption isotherm, Chemical Engineering Journal, 24, 2006, 103 – 110.

[2]. V.K. Gupta, S.K.Srivastava, and D. Mohan, Equilibrium uptake, sorption dynamics, process optimization and column operations for

the removal and recovery of malachite green from wastewater using activated carbon and activated slag, Ind.Eng.Chem.Res, 36, 1997, 2207 – 2218.

[3]. M. Jayaranjan, R. Arunachalam, and G. Annadurai, Use of low cost nano – porous materials of pamelo fruit peel wastes in removal

of textile dye, Research journal of environmental sciences. 55, 2011, 434 – 443. [4]. Y. Guo, S. Yang, and Z. Wang, Adsorption of malachite green on micro and mesoporous rice husk based activated carbon, Dyes

and pigments, 56, 2003, 219 – 229.

[5]. N. Gupta, A.K. Kushwaha, and M.C. Chattopadhyaya, Kinetics and thermodynamics of malachite green adsorption on banana pseudo-stem fibers, J.Chem. pharm, 3, 2011, 284 – 296.

y = -4E-07x + 4.029

R² = 0.925

y = -6E-07x + 3.985

R² = 0.911

y = -1E-06x + 4.017

R² = 0.969

y = -2E-06x + 3.979

R² = 0.969

y = -2E-06x + 3.848

R² = 0.929

y = -2E-06x + 3.775

R² = 0.918

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

0.00 500000.00 1000000.00 1500000.00 2000000.00 2500000.00 3000000.00

ln q

e

E2

30°C

40°C

45°C

50°C

55°C

60°C



[6]. K.Kadirvelu, M.Kavipriya, C.Karthika, M. Radhika, N.Vennilamani, and S.Pattabhi, Utilization of various agricultural wastes for

activated carbon preparation and application for the removal of dyes and metals ions from aqueous solutions, Bioresource

Technology, 87, and 2003, 129 – 132. [7]. A.Mittal, Adsorption kinetics of removal of a toxic dye, malaghite green, from waste water by using hen feathers, J,.Hazard.Mater,

113, 2006, 196 – 202.

[8]. I.A Rahman, B. Saad, S.Shaidan, and E.S.SyaRizal, Adsorption Characteristics of malachite green on activated carbon derived from rice husks produced by chemical – thermal process, Bioresour.Technol, 96, 2005, 1578 – 1583.

[9]. S. Senthilkumar, P.R. Varadarajan, K.Porkodi, and C.V.Subhuraam, Adsorption of methylene blue onto jute fiber carbon: kinetics

and equilibrium studies, Journal of colloid and interface science, 284, 2005, 78-82. [10]. K.V. Kumar, Optimum sorption isotherm by linear and non-linear methods for malachite green onto lemon peel, Dyes and

pigments, 74, 2007, 595 – 597.

[11]. Praveen Sharma et.al., COD reduction and colour removal of simulated textile mill wastewater by mixed bacterial consortium, Rasayan. j. chem, 3, 2010, 731-735.

[12]. A.K. Jain, V.K. Gupta, and A. Bhatnagar et al., Utilization of industrial waste products as adsorbents for the removal of dyes,

J.Hazard Mater, 101, 2006, 31-42. [13]. G. McKay, J.F. Porter and G.R. Prasad, The Removal of Dye Colours from Aqueous Solutions by Adsorption on Low-Cost

Materials, Water Air Soil Pollution, 114, 1998, 423-438.

[14]. K. Ranganathan, K. Karunagaran, and D.C. Sharma, Recycling of wastewaters of textile dyeing industries using advanced treatment technology and cost analysis—Case studies, Resources, Conservation and Recycling, 50, 2007, 306–318.

[15]. M. Dojan, M. Alkan, and Y. Onganer, Adsorption of methylene blue from aqueous solution onto perlite, Water. Air. Soil. Pollut,

120, 2000, 229-249. [16]. R. Rajeshkannan, N. Rajamahan, and M. Rajasimman, Removal of malachite green from aqueous solution by sorption on hyeilla

verticllate biomass using response surface methodology, Fron.Chem.Eng.China, 3, 2008, 146 – 154.

[17]. Theivarasu, S. Mylsamy, and N. Sivakumar, Coca shell as adsorbent for the removal of methylene blue from aqueous solution: Kinetic and equilibrium study, Universal journal of environmental research and technology, 2011, 70 – 78.

[18]. J. Zhang, Y. Li, C. Zhang, and Y. Jing, Adsorption of malachite green from aqueous solution onto carbon prepared from Arundo

donax root, J.Hazard.Mater, 50, 2008, 774. [19]. O. Yavuz, and H. Aydin, Removal of direct dyes from aqueous solution using various adsorbents, polish journal of environmental

studies, 15, 2006, 155-161.

[20]. R. Sivaraj, et al., Orange peel as an adsorbent in the removal of acid violet 17 from aqueous solutions, technical note, waste management , 21, 2001, 105-110.

[21]. A.R.Tehrani-Bagha, H.Nikkar, N.M.Mahmoadi, M.Markazi, and F.M.Menger, The sorbtion of cationic dyes onto Kaolin: Kinetic,

isotherm and thermodynamic studies, Desalination, 266, 2011, 274 – 280. [22]. M.C. Somasekhara reddy, Removal of direct dye from aqueous solutions with an adsorbent made from tamarind fruit shell, an

a’gricultural solid waste, journal of scientific & industrial research, 65, 2006, 443-446.

[23]. V. Ponnusami, V. Kritika, R. Madhuram, and S.N. Srivastava, Biosorption of reactive dye using acid – treated rice husk, J Hazard Mater, 142, 2007, 397 – 403.

[24]. P. Velmurugan, V. Rathina Kumar, and G. Dhinakaran, Dye removal from aqueous solution using low cost adsorbent, International

journal of environmental sciences, 7, 2011, 1492-1503.

[25]. S. Wang, Y. Boyjoo, and A. Choueib, A comparative study of dye removal using fly ash treated by different methods,

Chemosphere, 60, 2005, 1401-1407. [26]. G. Krishna, Bhattacharyya, and Arunima Sharma, Kinetics and thermodynamics of Methylene Blue adsorption on Neem

(Azadirachta indica) leaf powder, Dyes and Pigments, 65, 2005, 51-59.

[27]. V.K. Gupta, A. Mittal, L.Krishnan, and V.Gajbe, Adsorption kinetics and column operations for the removal and recovery of malachite green from wastewater using bottom ash, Separa. Puri. Technol, 40, 2004, 87–96.

[28]. B.H. Hameed, A.K. Ahmad, and K.N.A. Latiff, Adsorption of basic dye (methylene blue) onto activated carbon prepared from

rattan sawdust, Dyes and Pigments, 75, 2006, 143-149. [29]. R. Gong, Y. Jin, F. Chen, and J. Chen, Enhanced malachite green removal from aqueous solution by citric acid modified rice straw,

J.Hazard. Mater, 137, 2006, 865 – 870.

[30]. V.K. Grag, Raksh Kumar, and Renuka Gupta, Removal of malachite green dye from aqueous solution by adsorption using agroindustries waste, A case study of phosopisceneria, Dyes and Pigments, 62, 2004, 1 – 10.

[31]. Jumasiah, T.G. Chuah, J. Gimbon, T.S.Y. Choong, and I. Azni, Adsorption of basic dye onto palm kernel shell activated carbon:

sorption equilibrium and kinetics studies, Desalination, 186, 2005, 57–64. [32]. C. Namasivayam, R.Radhika, and S. Subha, Uptake of dyes by a promising locally available agricultural solid waste: coir pith,

Waste Management, 21, 2001, 381 – 387.

[33]. Papita Saha, Assessmant on the removal of methylene blue dye using tamarind fruit shell as biosorbent, Springer science + business media, 213, 2010, 287-299.

[34]. M. Sarioglu, and U. Atay, Removal methylene blue by using biosolid, global nest Journal. 8, 2006, 113 -120.

[35]. S.P.S. Syed, Study of the removal of malachite green from aqueous solution by using solid agricultural, Waste.Res.J.Chem.Sci, 1, 2011, 88.

[36]. Tabrez a khan et.al., Removal of some basic dyes from artificial textile wastewater by adsorption on Akash kinari coal, Journal of

scientific and industrial research, 63, 2004, 355 – 364. [37]. I.A.W. Tan, A.L. Ahmad, and B.H. Hameed, Adsorption of basic dye using activated carbon prepared from oil palm shell: batch

and fixed bed studies, Desalination, 225, 2008, 13–28.

[38]. V. Vadivelan, and K.V. Kumar, Equilibruim, kinetics, mechanism and process design for the sorption of methylene blue onto rice husk, J. Colloid Interf Sci, 286, 2005, 90-100.

Saravanan N,. " Adsorption of Malachite Green Using Activated Carbon From Copper Pod."

IOSR Journal of Applied Chemistry (IOSR-JAC) 11.8 (2018): 33-45.

adsorption of malachite green using activated carbon from … · 2018-09-01 · adsorption of...

Documents